Twin cylinder steam engine



R E m H s M TWIN CYLINDER STEAM ENGINE Filed April 9, 1955 INVENT OR.

ATTORNEYS 3 v Kai 2&2

Wan, l4, I

i' 'atenteci Jan. 14, 1936 UNITED STATES PATENT OFFICE TWIN CYLINDER STEAM ENGINE Application April 9, 1935, Serial No. 15,477

2 Claims.

Thisis a continuation in part of my co-pending application Ser. No. 531,715 filed April 21, 1931.

This invention relates to .twin cylinder steam engines and, more particularly, to steam engines of the double acting type having twin cylinders cast together as a single casting.

The problem of maintaining the parts of a twin cylinder steam engine in alinement and to obtaina compact engine has made it desirable to cast or otherwise form as manyof these parts integral as possible. The forming of the parts integral has, however, been attended by considerable difficulty; since the metal of which the parts are made expands upon heating; and unless all of the parts are heated equally, the alinement between the parts is not maintained. A Still further complication is introduced when the steam intake manifold and the exhaust manifold are also formed integral with the steam cylinders.

My invention overcomes 'these various objections and provides a steam engine in which inequalities of expansion may be absorbed and alinement insured at working temperatures.

The various features of my invention are illustrated in the accompanying drawings, in

which:

Fig. 1 is a view, partly in elevation and partly in central vertical section, of a vertical double acting steam engine embodying my invention and having twin cylinders cast together as a single casting; Fig. 2 is a view principally in elevation of a steam engine of the type shown in Fig. 1,

parts being omitted for the sake of simplicity, so as to better illustrate my invention; Fig. 3 is a section on the line 3-3 of Fig. 2; Fig. 4 is a horizontal section through the steam intake manifold taken on line 4-4 of Fig. 1; Fig. 5 is a horizontal section through the exhaust manifold taken-on line 5--5 of Fig. 1,-and Fig. 6 is a View in elevation of a modified form of myinvention with a power take-off at one end of the crank shaft, andwith a floating outboard bearing, parts being broken away to facilitate illustration.

In the preferredembodiment of my invention shown in Figs. 1, 2, 3,4, and 5, the steam cylinders l and 8 are integral with steam intake mani- .of the-engine. 'By means'of webs M, l5, and I6,

the support I3 is braced so thatitis rigid with the frame 1 1.

Between the webs M and I5 is a stiffening web I! and between the webs l5 and i6 .is a similar web H3. Webs l9 and 20 extend upwardly from the webs Id and i6, respectively. The .web 19 .does not cooperate directly with the support l3, while the Web 28 does directly and rigidly brace the support It. The supDQrt I3 is in the form of a ring surrounding the main bearing; and a minor portion of this support, indicated by the numeral 2!, is flexible so as to permit clamping within the same of the housing .22 of the :main bearing. The ring shaped support 13 is split at 23, as shown in Fig. 3. The two parts of the clamp are provided with openings through which extends a stud 26. Nuts 25 onthe two ends of the stud may be drawn up to clamp the housing 22 within the support 13.

Bearing support It also can be widened by inserting a wedge in opening 23 in order to facilitate the assembly of the crank shaft with the frame vI I, so that the main bearings may be received within the bearing supports l3.

The main bearings are constituted by roller bearings .26. In order that the crank shaft 21 may be assembled with the frame, so as to be rotatably supported by the roller bearings 26, the cranks 28 are made separate from the shaft 21. Openings 29 are provided in the frame H in alinement with the main bearings, these openings 29 being supplied with cover plates 30. The crank shaft 2'5 extends across the space 12 through openings Si in the frame I l these openings being supplied with apertured cover plates 32. It will be apparent that inas- .much as the cranks 28 are made separate from the crank shaft 21, it is possible to mount the races of the roller bearings 26 on the shaft 21. The assembly of the crank shaft and roller bearings may be positioned within the supports l3; and by means of the studs 2 and nuts 25, the housings 22 of the roller bearings 26 may be secured in position. The cranks 28 may be pressed onto the crank shaft 27. In the embodiment shown, keys 33 secure the cranks 28 to the shaft 21.

The pistons which are reoiprocable within the cylinders 7 and 8 are connected to cross-heads 34, reciprocable in cross-head guides 35. I prefer to form these guides 35 integral with the frame I I. Due to the greater extremes of temperature to which the steam end of the engine is subjected, the integral construction provided by my invention might lead to misalinement of the parts, if the cylinders l and 8 were in direct alinement with the cross-head guides 35 when the entire structure is cold. For this reason, I bore the cylinders I and 8 on axes slightly offset toward each other, with respect to the cross-head guides, the amount of offset being sufficient to cause the cylinders I and 8 to be brought into alinement with the cross-head guides 35 by expansion of the metal when heated up during operation of the steam engine. In Fig. 2, the center lineof the cylinder 8 is indicated by the line a and the center line of the cross-head guide 35 is indicated by the line b. As indicated in Fig. 2, these lines are slightly offset when the structure is cold. As the engine heats, the cylinders slide into alinement, sufficient clearance 35 being provided about the bolts securing the cylinders to the frame to permit this movement of the cylinders (Fig. 1).

Between the cross-head guides and the cylinders I and 8 are spacers 36. In the embodiment shown, these spacers are integral with the frame I I, thereby avoiding opportunity for the cylinders I and 8 to get out of alinement after the same have been machined.

I further prefer to form the steam intake manifold 9 and the steam exhaust manifold ID integral with the cylinders 1 and 8. In the embodiment shown, the cylinders I and 8 are double acting and are provided with ports 4| and 42 at the two ends of the cylinders respectively. A piston valve 31 cooperates with the steam intake manifold, the exhaust manifold and the ports ll and 42 to control the operation of the steam engine, this valve being actuated by suitable valve gear 38. A cylinder head 39 closes the top of each of cylinders 1 and 8, while a cylinder head 40 closes the bottom of each. The assembly of the cylinder block and the cylinder heads is bolted to the spacers 36, which in the embodiment shown are integral with the frame II.

Since the metal in the steam intake manifold and in the exhaust manifold is subject to a very substantial variation in temperature, and since the cylinders and 8 and the steam intake manifold and the exhaust manifold are formed integral, the expansion of the metal, resulting from the heating up of these parts, presents a difficulty in maintaining alinement of the cylinders. Accordingly, I provide in the steam intake manifold 9, a bend 33 so that the manifold will flex, rather than push the cylinders l and 8 out of alinement as the manifold heats up. A similar bend M is provided in the exhaust manifold IE]. It will be apparent, therefore, that the portions of the two manifolds which engage the cylinders 1 and 8 are not subject to as substantial a lateral movement, due to expansion, as would be the case if these manifolds pushed directly outwardly instead of being provided with an expansion bend which permits part of the expansion to be taken up by the bend. Inequalities in temperature between the inlet and exhaust manifolds and inequal expansions resulting therefrom are taken up in these bent parts and stresses thereby avoided. The exhaust manifold is not heated to so high a temperature as the steam intake manifold and to a certain extent the bending of the manifolds assists in preventing distortion of the cylinders 1 and 8, so as to destroy alinement of the same. The adjacent walls of the manifolds 9 and I are slightly spaced, as shown in Figs. 1, 2, and 3. This provides a chamber 45 between the manifolds which aids in insulating the hotter steam intake manifold from the cooler exhaust manifold. The steam intake manifold is at a higher level than the exhaust manifold I0 and to a certain extent, overlies the latter.

It will be apparent from the above description that my improved construction permits heat expansion within the integral cylinder block without causing excessive wear in the bearings due to misalinement. The centers of the cylinders T and 8 will be in proper alinement when heated up and, therefore, the setting up of excessive stresses is avoided. The main bearings are carried by supports formed integral with the frame H and are, therefore, properly alined. There is 10 not the same possibility of inaccurate adjustment, since the supports are machined directly in the frame H. This type of support for the main bearings has the further advantage over the type having bearing caps held down with bolts that there is not the possibility of the bolts becoming bent, shorn or stretched. Moreover, the axis of the bore of the supports l3 does not deviate and perfect alinement is, therefore, promoted, this being a considerable advantage over the type in which the bearing cap must be tightened over the bearing.

In the embodiment of my invention shown in Figs. 1 and 2, the power take-off member, such as a gear or sprocket, may be keyed at 46 to the crank shaft 21. This power take-01f member is accordingly disposed intermediate the cranks 28. In the embodiment shown in Fig. 6, the frame and the steam end of the engine are identical with that shown in Fig. 2. The crank shaft 41 has a crank 48 formed integral therewith. The openings 29 are identical with the openings shown in Fig. 2. Inasmuch as the second crank 28 is formed separate from the crank shaft 41, the shaft may be supported in roller bearings similarly, as in the embodiment shown in Fig.- 2. The cover plate 49 shown in Fig. 6, is provided with a pair of roller bearings 50 for rotatably supporting the projecting end 5| of the crank shaft 41. These roller bearings are contained within a housing 52 fitting an opening in the cover plate 49. The inner races .of the bearings are held in position on shaft 41 by a nut 56. The outer races may be adjusted within the housing 52 by a gland member 51, which serves also as an oil seal. The main bearing 26 is contained within a housing 58 which is secured in position in the bearing support l3. The housings 22 and 52, on the other hand, may slide relative to their respective supports 13 and $9. This takes care of possible expansion, stresses in the bearings and in the crank shaft. A power take-off member may be secured by the key 60 to the shaft 41 in the space I2 between the two divisions of the frame II; and on the projecting end 5| may be secured by the key 6| or other suitable means a second power take-off member. It will be apparent, therefore, that I have provided a steam engine which may be supplied with a crank shaft on which is mounted a single power take-off member, or with a crank shaft on which is mounted a pair of power take-off members. In the embodiment shown in Fig. 2, this power take-off member is disposed in the space l2; in the embodiment shown in Fig. 6, one of the power take-off members is disposed intermediate the 65 cranks and the other on a projecting end of the crank shaft. The steam engine is, therefore,

adapted to a variety of different driving connections.

While I have described in specific detail two embodiments of my invention, it will be apparent that various additions, substitutions and changes can be made therein, without departing from this invention, and under the scope of the following claims.

What I claim is:--

1. A twin cylinder engine comprising an integral cylinder block having a pair of cylinders, one cylinder at each end of the block, inlet and outlet manifolds positioned centrally and spaced from each other, control valves between said cylinders and said manifolds and separate spaced connecting passages between said cylinders, valves and manifolds, said passageways having expansion bends to prevent twisting said cylinders out of alinement through unequal expansion of said passageways, a bearing frame having crosshead guideways alined with said cylinders when said cylinder block is at working temperatures, and bolts securing said frames to said cylinder block and being provided with clearance spaces to permit said cylinder block to contract and draw said cylinders out of ali'nement with said guideways when cooled below working temperatures.

2. A twin cylinder engine comprising an integral cylinder block having a pair of cylinders, one cylinder'at each end of the block, inlet and outlet manifolds positioned in said block between said cylinders and control valves between said cylinders and said manifolds, said cylinders having pistons and cross heads, a pair of spaced cross head guides, one for each cylinder, integrally mounted to aline with said cylinders when the latter are at working temperatures and. offset therefrom when said cylinders are at the same temperatures said guides and bolts securing said guides to their respective cylinders and being provided with clearance spaces to permit relative movement to and from alinement.

JOHN M. SHIMER. 

